Studies are proposed to investigate the relationships between gonadal hormones, the brain and behavioral. We will study the molecular mechanisms of hormone action, namely the binding of estradiol to cytoplasmic receptors, the translocation of estrogen receptor complexes into the cell nucleus and hormone receptor complex binding to nuclear chromatin material in estrogen concentrating cells in brain tissue. A varity of anti-estrogens and extensive pharmacokinetic analyses will be used to detect critical molecular events which mediate estrogen's action on sexual behavior. To determine that hormonal events at the molecular level are related to the targeted behaviors, we will study the molecular actions of hormone under conditions and in animals which do and do not show hormone-induced changes in behavior. Males and females and males and females hormonally manipulated during sensitive periods of perinatal development will be used for this purpose. By using such animals we will also determine some of the neural sequelae of sexual differentiation process. By using a variety of treatments during development, we will obtain information on which steroid(s) is critically involved in the sexual differentiation of the brain.